This invention relates to an apparatus for removing entrained gas from a liquid and, more particularly, to a fuel/air separation apparatus to remove entrained particle contaminants, air and vapor from a liquid.
Today's internal combustion engines typically utilize a fuel injection type system to inject fuel into the engine cylinder. The fuel is delivered to the cylinder in precise quantity of air. The ratio of air/fuel mixture is tightly controlled in order to maintain a smooth and efficient running engine. If air or other gaseous vapor is entrained with the fuel and injected into the cylinder, the air/fuel ratio may be affected resulting in a rough running engine and loss of power and efficiency. Air and/or vapor in a fuel injector delays injection of fuel into the cylinder retarding the engine timing. Additionally, additional air or vapor may lower the cylinder air pressure resulting in the cylinder rings not tightly seating against the cylinder wall and allowing blow-by and increasing vehicle exhaust emissions.
U.S. Pat. No. 5,355,860 discloses a three-filter system for removing entrained undesired gas from diesel fuel. There are many deficiencies with the system described and claimed in the '860 patent One deficiency is the entrained gas is only removed on the inlet side of the filter element which results in dirty fuel and air being returned to the fuel tank. Another deficiency is the system requires that the filter clement is completely submerged below the surface of the fuel, If air comes into contact with the filter element it will pass through the filter element, through the outlet to the engine. A third deficiency is a vacuum is created on the inside of the filter element because the filter element presents a barrier to the passage of fuel, and the overflow tube is a free unobstructed opening to the fuel tank. This vacuum causes air and vapor bubbles to form on the inside of the filter element, which are then carried through the outlet to the engine.
U.S. Pat. No. 5,746,184 discloses a system for removing undesired gas from diesel fuel and has been sold commercially under the trade names Fuel Preporator® model Nos. FP-1200, FP-135 and FP-133A, and the AirDog Fuel Preporator® model No. FP-80, available from Ekstam Worldwide. The '184 patent is a continuation-in-part of the '860 patent and adds a new and previously unclaimed second embodiment to the single embodiment disclosed and claimed in the '860 patent. The second embodiment set forth and claimed in the '184 patent also suffers from many deficiencies. Like the system disclosed and claimed in the '860 patent, the '184 includes an opening to the return line on the inlet side of the filter element causing dirty fuel and air to be returned to the fuel tank. The '184 system also includes an opening on the inside of the filter element connected to the return line. However, the pressure on the inlet side of the filter element must rise to a level to force the air across the filter element to the interior. In practice the pressure normally will not reach this level and dirty fuel and air will be returned to the fuel tank through the inlet side fuel return line, If the pressure rises to the necessary level to force the air through the filter element due to an obstructed inlet side fuel return line opening, for example, a vacuum may be created on the inside of the filter element creating gas bubbles at the outlet tube opening and drawing bubbles into the outlet.